Radiation dose reduction in computed tomography (CT) using a new implementation of wavelet denoising in low tube current acquisitions

Despite the good general patient acceptance, high patient comfort, safety and precision in the needle placement, exposure to radiation in computed tomography (CT)- guided spinal interventions remains a serious concern, and is often used to argue against its use. The aim of this study was to determine the technical possibilities of reducing the radiation dose in CT-guided epidural and periradicular injections in lumbar spine. We evaluated the possibilities of reducing radiation dose to the patient and operator during CT-guided injections on the lumbar spine using the following steps: significant reduction of the tube current and energy used for the topogram-acquisition, narrowing the area of interest in spiral CTmode and reduction of tube current and radiation energy in the final intervention mode. Fifty-three CT-guided spinal injections were performed in the lumbar spine (34 epidural lumbar, 19 lumbar periradicular) using a low-dose protocol in non-obese patients and compared with 1870 CT-guided injections from the year 2010, when a standard dose protocol was used. Technical considerations on radiation dose reduction were provided. An average dose reduction of 85% was achieved using the low-dose protocol in CTguided epidural and periradicular injections in lumbar spine without showing any effect on safety or precision.

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Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

Journal of Clinical Imaging Science ◽

10.4103/2156-7514.137826 ◽

2014 ◽

Vol 4 ◽

pp. 38 ◽

Cited By ~ 12

Author(s):

Lukas Ebner ◽

Felix Knobloch ◽

Adrian Huber ◽

Julia Landau ◽

Daniel Ott ◽

...

Keyword(s):

Computed Tomography ◽

Soft Tissue ◽

Radiation Dose ◽

Dose Reduction ◽

Integrated Circuit ◽

Chest Ct ◽

Back Projection ◽

Dose Length Product ◽

Chest Computed Tomography ◽

Tube Current

Objective: The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT) by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP) and an iterative reconstruction (IR) algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany) was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP), SOMATOM Definition Flash (IR), and SOMATOM Definition Edge (ICD and IR). Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP) with FBP for the average chest CT was 308 mGy*cm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGy*cm ± 68.8 (P = 0.0001). Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGy*cm ± 54.5 (P = 0.033). The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR) was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048). Overall contrast-to-noise ratio (CNR) improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

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